Boeing Had Considered Battery Fire Nearly Impossible, Report Says

By

Andy Pasztor

Updated March 7, 2013 10:03 p.m. ET

The battery that burst into flames two months ago on a Boeing Co. 787 jet in Boston experienced dramatic power fluctuations and other failures its designers had considered practically impossible, according to the latest report by U.S. air-safety regulators.

Their update, however, didn't clear up the mystery over the fire's initial cause.

The National Transportation Safety Board interim report released Thursday did provide...